Original Article
Lesion of the Nucleus Solitarius Leads to Impaired Laryngeal Sensation in Bulbar Palsy Patients

https://doi.org/10.1016/j.jstrokecerebrovasdis.2011.06.007Get rights and content

Background

In order to clarify the laryngeal sensation of bulbar palsy patients, we studied the relationship between laryngopharyngeal sensation and brainstem lesion in patients with dysphagia caused by bulbar palsy.

Methods

Fifteen patients with lateral medullary infarction and dysphagia were included in this study. We performed laryngeal sensory test using the flexible laryngoscope and probes method previously developed by Yaguchi et al. The test sites included the right and left tip of the laryngeal surface of the epiglottis and bilateral arytenoid regions. Lesion sites were identified by magnetic resonance imaging and classified horizontally according to Kim's classification. We also used the anatomical atlas Cytoarchitecture of the Human Brain Stem to determine whether the lesions included the nucleus solitarius and nucleus ambiguus.

Results

Eight cases had normal sensation and 7 cases had decreased sensation of the affected side of the epiglottis and arytenoid region. The lesions of decreased laryngeal sensation group were classified horizontally as large type or dorsal type and included the nucleus solitarius. Decreased laryngeal sensation was significantly correlated with lesions that included the nucleus solitarius (Fisher exact test; P = .026).

Conclusions

This study clarifies that patients with dysphagia caused by bulbar palsy may present with laryngeal sensory impairment of the affected side and laryngopharyngeal movement disorder. The important finding is that damage to both the nucleus solitarius and ambiguus cause dysphagia accompanied by decreased laryngeal sensation and that the lesions are relatively extensive and affect the middle level of the dorsal medulla.

Section snippets

Methods

Fifteen bulbar palsy patients (9 males and 6 females; average age 68.1 years [range 44-88 years]) who were admitted to our hospital or treated as outpatients were included during the study period (August 2009 to April 2011). The brainstem lesion site occurred on the right side in 6 cases and on the left side in 9 cases. The sensory test was performed in cases from 13 days to 10 years after onset. All 15 cases were found to be LMI. A history of pneumonia was observed in 4 cases. Surgery to

Results

All cases presented with the curtain sign.

Discussion

This study is, to our knowledge, the first to clarify that patients with dysphagia caused by bulbar palsy may present with laryngeal sensory impairment on affective side. The important finding is that the lesions of patients with decreased laryngeal sensation included the nucleus solitarius.

Laryngopharyngeal mucosal sensation is under multiple controls (i.e., pharyngeal, lingual, and tonsillar branches of cranial nerve IX, pharyngeal branch of cranial nerve X, and superior and inferior

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